MARSHALL JCM 800 DUAL CHANNEL
SYNERGY THREE-TUBE PREAMP MODULE
Few amplifiers have achieved the near-mythical status of the Marshall JCM 800. When it appeared in the early 1980s, it didn't just define an era; it set it on fire. Ushering in a new generation of tones, the JCM 800 became the iconic voice of hard rock and heavy metal. Powerful, aggressive, and quintessentially British. It took the fundamental crunch of the Plexi and added the gain, power, and precision that propelled an entire generation of guitar virtuosos.
The Marshall JCM 800 2203 (100W) and 2204 (50W) circuits, with their single channel, cascading gain stages, and mid-range signature, offered an unmatched level of authority and articulation. It was the perfect balance of power and precision. For
countless guitarists, the JCM 800 is not just an amplifier: it is THE amplifier.
Today, Synergy and Marshall partner once again to bring you, for the very first time, this legend in a three-tube, two-channel preamp module. Utilizing the original Marshall circuit, the JCM 800 module delivers the raw energy, attack, and precise overdrive of the iconic vertical-input
2203/2204 amplifiers. Whether you are looking for the three-dimensional crunch of 80s rock or
high-gain saturation for modern metal, the JCM 800 module provides the legendary sonic experience
that defined a generation.
TWO-CHANNEL, THREE-TUBE PREAMP
Each of the two identical channels of the JCM 800 features independent controls for preamp, bass, middle, treble,
presence, and volume, giving you total mastery over your gain and sonic response. From dynamic low-gain crunch to high-gain saturated sustain, the JCM 800 module
captures every nuance of the original amp's tone. Independent master volume controls for each
channel allow you to precisely balance rhythm and solo levels while maintaining the dynamic character
and harmonic complexity of the amp.
THREE-TUBE MODULE WITH INTEGRATED 0-WATT POWER AMPLIFIER - A SYNERGY FIRST
The JCM 800 module introduces Synergy's revolutionary three-tube architecture, a first in modular preamp design.
Adored by generations of musicians, the original JCM 800 revealed its full power at full volume, thanks to the
magical interaction between its preamp and power amp stages. Synergy has now captured this
same raw energy and incomparable feel in a compact modular format. Two 12AX7 tubes power the preamp,
while a third 12AX7 drives the integrated 0-watt power amp and phase inverter. With the JCM 800 module,
you get the swagger, the feel, and the harmonic richness of a cranked JCM 800 head, at any volume.
The JCM 800 module offers the power, grit, and bite that made this amp an icon of rock history,
while propelling Synergy's modular platform toward bold new sonic horizons.
BRIGHT AND HIGH/LOW INPUT SWITCHES
Building on the amp's original design, the JCM 800 module offers increased flexibility with two
key features:
• Bright Switch: A three-position switch allows you to choose between two bright capacitor values or to
disable it completely. This lets you adjust the attack and clarity of the preamp stage, from a
precise and biting sound to a warm and smooth one. It's like modifying the bright capacitor of a vintage 2203,
without the need for soldering. • High/Low Input Selector: Faithfully reproduces the two input jacks of the original JCM 800, allowing you to toggle between the high-gain "Lead" input and the lower-gain "Normal" input.
This lets you switch instantly from a classic, punchy crunch to modern saturation.
CATHODE SELECTOR FUNCTION
The Marshall JCM 800 module is equipped with a three-position selector on the PCB, allowing you to
configure the bass response of the input tube to match the original circuit of the selected module. These
settings influence feel and precision. Every amp designer uses a specific combination of components
for their input tube circuit. We have selected the three most popular combinations,
accessible via this selector: position 1 (1.5 kΩ resistor and 22 µF capacitor), position 2 (2.7 kΩ resistor and 0.68 µF capacitor), and position 3 (1.8 kΩ resistor and 1 µF capacitor). Of course, you can
experiment and try different positions to determine which suits you best. The JCM 800 module is preset to the
center position (2.7 kΩ resistor and 0.68 µF capacitor).
Synergy hardware and interchangeable preamps are protected by a U.S. patent.
The JCM800 module is compatible only with SYNERGY hosts (SYN-1, SYN-2, SYN-20IR, SYN-30, SYN-50).
It is incompatible with any other hardware from any other manufacturer. MARSHALL THREE-TUBE MODULE SPECIFICATIONS:
• Authentic three-tube preamp inspired by the legendary Marshall JCM 800 (2203/2204
Vertical Input)
• 3 x 12AX7 preamp tubes for optimal harmonic richness and dynamics
• Integrated 0-watt power amplifier and phase inverter for a traditional amp-like feel
• Two identical channels, each with the following controls: Preamp, Bass, Middle, Treble, Presence
• Independent master volumes for rhythm and solo
• Bright selector (three positions) to adjust bright capacitor value to shape your tone
• High/Low input selector reproducing the original JCM 800 input
behavior
• PCB-mounted cathode selector for adjustable tube response
• Easy installation and removal from Synergy preamp docking stations